And he believes the England midfielder deserves credit for ensuring he left Villa for a transfer fee rather than on a free.

"I'm not too surprised," Lambert told BBC 5Live.

Aston Villa's Fabian Delph at pre season training

"I think Fabian has every right to change his mind whenever he wants to do it.

"When a club like Manchester City come calling.... let's be honest they are going to be in the hunt for the Champions League, the league title, the FA Cup, the Capital One Cup, they are going to be involved in all fronts.

"I know Fabian made the choice he thought was right a week ago and obviously he's had a change of mind. He's quite entitled to do it. I think it was really good the way he did it. when he signed a contract so the club could get some money back for him. I think people have got to look at that as well.

"The guy signed a contract thinking if I leave at the end of the season I'm not going to get the club anything. but he actually signed and the club will get that release clause."

There has been speculation that Christian Benteke's looming move to Liverpool was a factor in Delph's change of heart.

But Lambert believes it is more to do with how Villa have struggled during the past half a decade.

Christian Benteke of Aston Villa (L) celebrates with Fabian Delph

"I don't think Christian going - if he does go - will make a lot of difference to him," he said.

"I think the way the club's been going for the last four or five years I think has been a big thing for him.

"Christian maybe going might have played a part but I wouldn't have thought it would've played 100 per cent behind it."

Lambert was proud Delph won his first senior international cap while he was manager at Villa.

He added: "When I first went to Villa Fabian was just coming back from injury and I thought we had to get this lad fully fit to get him sustaining playing football.

"In nearly three years I was there he was exellent for me, he really was. I said last year maybe England should look at him. He got his debut when I was there, which was great."